Compact ladder type SAW resonator filter

A SAW ladder filter can consist up to 10 resonators. To avoid the interaction between resonators, they are placed in separate acoustic tracks and that increased the sizes and makes interconnection between resonators long and complex. This paper introduces a method to place 2 or more resonators in one acoustic track with common reflectors and connect them parallel or serial electrically. Ladder filter becomes small and interconnections become short and easy. The results of simulation are presented along with experimental data. The example is a ladder filter with 8 resonators placed in 4 acoustic tracks that allowed size reduction and insertion loss improvement.